This invention concerns an illuminating apparatus having a light source and a first reflector directed toward the light source.
When illuminating for filming, television production, and photography it can be desirable not to employ direct lighting. Direct light from a lamp creates, because of a small radiation area, or area of emission, hard shadows which are not desirable for particular illumination purposes. In this regard, it is particularly difficult to illuminate long narrow corridors. Illumination of such corridors with prior-art lamps arranged linearly on a ceiling, which display a substantially uniform light radiation to all sides, is unsuitable for this purpose. An actor moving along a length of such a corridor would be illuminated to a greater degree as he approaches a lamp. Thus, an expression, that the actor's face "burns up" as he approaches a lamp, is used in the trade. When the actor is directly under the lamp, he is illuminated from directly above, whereby his eyes suddenly appear to be in deep shadow. Such effects are reduced by employing illumination systems which exhibit light distribution having bat-wing characteristics. "Bat-wing-characteristics" means, in this regard, that for a hanging arrangement of an illumination device, light is directed vertically sidewardly downwardly, no light is emitted directly downwardly, the intensity of the radiated light changes with beam angle, the light intensity is reduced with an increase in the steepness at which light is directed downwardly, and transitions between illuminated and non-illuminated areas are soft or gradual. A light apparatus with bat-wing-characteristics is schematically represented in FIGS. 18 A-D.
Open spotlights, or floodlights, cannot create such bat-wing characteristics of light distribution. An open floodlight has a reflector adjacent a light source. The reflector directs the light. In this manner a radiation surface, or area, is enlarged. However, the radiation surfaces for many such floodlights are still relatively small, and definite shadows, with hard shadow edges, are created therewith.
Other floodlights include a lamp, a reflector and a lens. Such lenses are made as Fresnel, or stepped, lenses or as normal condenser lenses. In this manner, light direction as well as light distribution can be better influenced. Still, however, a radiation area remains small. For many illuminating operations, therefore, a diffusion material, which is more-or-less light-transmissive and which more-or-less scatters light, is positioned at smaller or larger distances in front of the floodlight. The thicker this diffusion material is, the greater are the diffusion angles of light that are emitted from the diffusion material. In this manner, the radiation angle is more or less uncontrolled. If light should be shaded from an object, opaque sheets can be used which must, however, be positioned, separate from the lamp at appropriate spacings in front of the diffusion material.
When a light source is to be employed which creates soft edges, there are various apparatus known in the prior art for enlarging the radiation area.
A reflection umbrella, or diffusion umbrella (screen), is known from a publication, Dedo Weigert Film, Licht (see pages J3, J9, J17 and J30). With this arrangement, an umbrella, or screen, is opened adjacent a floodlight. The screen can have a reflecting surface. In this manner, the light that is reflected back from the screen can have a large radiation area. Such a screen can also be made of a translucent or transparent material so that the light which passes therethrough has a greater radiating area and, in this manner, creates a desired softness to shading. By employing a plurality of such reflection/diffusion screens at particular spacings from one another, from the lamp and from an object to be illuminated, it is often possible to achieve a relatively good illumination for one camera position. However, if the position of the camera is changed for a new adjustment, for example, from an end of the scene to the other, then a plurality of stands supporting the reflection/diffusion screens must be moved and a new arrangement of the reflection/diffusion screens must be employed. This is work and time intensive, which negatively impacts on production costs for corresponding film and photo sessions.
A further device in the prior art is a so called Chinese lantern. Structurally, this is similar to a child's lantern or a paper lamp shade that is employed in a living room. A diffusion material surrounds a light source almost completely. The light is emitted completely about the lamp shade in a uniform manner; however, it has no bat-wing characteristics in its intensity's distribution. An ability to influence a radiation direction is only possible to a limited extent.
The publication Dedo Weigert Film, Licht discloses further soft light attachments (see pages J51 and J52). These attachments are made of textile material which can be placed in front of many different types of floodlights. Four sides of these attachments are made of a textile material which is opaque, and reflective on its inner surfaces. A front side of each of these soft light attachments is covered with a diffusion material. By use of such attachments, large area light can be created that produces soft shade transitions. The light of such soft light attachments can also be modified by Jalousies or grids, which can limit radiation-direction areas of the lamp.
Such soft light attachments are often made to have a tent-like constructions, with an inner-reflecting and otherwise opaque material being stretched on four spars. Thus, when seen from an observation direction along a normal to the light radiation area they often haven a rectangular or square structure.
The publication Dedo, Weigert, Film Licht, (pages J57 and J58) discloses an illuminating apparatus having a light source, a reflector adjacent the light source and a substantially two dimensional light scattering attachment arranged on the reflector. This device is a collapsible (foldable) soft-light producing structure. In this device an opaque textile material having a reflecting interior surface forms sides. Also in this construction, a front area is covered by a diffusion material. Such umbrella-like, or tent-like, structures with spars are well known. Because of its structure, this soft-light apparatus does not create a light distribution having bat-wing characteristics.
German Patent Publication DE-39-37-889 discloses an electrical lamp with a, substantially, point light source and an adjacent first reflector. A pipe shaped body of light-transmissive material is mounted on the first reflector, on whose wall, depending upon an incident angle of light rays, a reflecting or light transmissive foil is surroundingly mounted. A second reflector whose dimensions are substantially the same of those of the first reflector is mounted on the pipe-shaped body at an end thereof opposite an end at which the first reflector is mounted. A diffuser is located within the pipe-shaped body. The diffuser is formed of a narrow body which extends from one end of the pipe-shaped body to the other end and which is arranged to be spaced from the foil over its entire length. In the lamp, according to German publication DE-39-37-889, this combination of diffuser and foil or film serves the function of a completely uniform pipe-shaped light source. A light distribution created by the lamp according to DE-39-37-889 has no bat-wing characteristics.
It is an object of this invention to provide a compact illuminating apparatus which gives off diffused light whose distribution has bat-wing characteristics.